Sedimentology and deformation styles of upper Pleistocene deposits in the Oak Ridges Moraine, southern Ontario

A study was conducted at the Dufferin Aggregates Mosport Pit to examine the sedimentary processes occurring during the formation of Oak Ridges Moraine deposits and the processes responsible for their deformation.; Detailed sedimentological analysis suggests an ice-proximal glaciofluvial setting for these deposits. Deformation structures found within silt, sand, and gravel were likely created through the loading of overriding flood deposits, melting of buried ice-blocks, and remobilization of saturated sediments. These ice-proximal glaciofluvial deposits likely represent a small portion of the topset deposits from a glacier-fed fan-delta. The possibility that these sediments are part of a much larger ice-walled esker deposit has not been ruled out. Incorporating the study of deformation structures with standard sedimentological techniques allowed for a better understanding of the processes that occurred during and after sediment deposition and the ice-proximal nature of the depositional environment.